This tube is found when u remove the silver engine cover.I need to buy this tube cos its broken. It looks like an exhaust oil channel (not sure). it was noted to be broken/cot during a recent service and I was told only citroen dealers can have it in stock.Car runs fine but I occasionally smell oil while driving.
It sounds like some kind of breather pipe to me, probably the best thing to do is to roll into your local Citroen dealer and ask someone in parts to look at it and they should be able to get you one then.
